(RNN) - One person is dead and 10 injured in London after a vehicle hit multiple pedestrians early Monday morning, London Metropolitan Police report. Police are treating the incident "as a potential terrorist attack," said Prime Minister Theresa May, who will chair an emergency meeting later Monday.

Officers were called to the scene at 12:20 a.m. Monday near Finsbury Park Mosque as people were leaving a service. Muslims currently are observing Ramadan, during which they fast from dawn to dusk and engage in intense prayer and feast at sundown.

One man was pronounced dead at the scene, though investigators say they aren't certain whether he died from the vehicle strike or from a health-related issue.

A 48-year-old man, believed to be the driver of the van, has been arrested, police said. He was taken to the hospital as a precaution and will later undergo a mental evaluation. Police said no other suspects have been identified or reported. The investigation of the incident is being carried out by the Counter Terrorism Command.

Neil Basu,Counter Terrorism Policing coordinator said all the victims of the attack were members of the Muslim community. Basu spoke to the media at 9:30 a.m. London time. Basu said police were able to take the suspect quickly because people at the scene managed to apprehend him. He thanked those people for their strength at a time when they must have been "incredibly shaken, incredibly scared and incredibly angry."

Cynthia Vanzella, who lives near the scene, told CNN she saw multiple casualties and at least one person who appeared to be badly hurt. She said a police officer was doing what looked like a "cardiac massage, as if they might have had a bad heart or something."

Vanzella said the north London community is very diverse, with churches of various faiths within blocks of one another. She said there has been no conflict among the groups in the past.

Numerous witnesses told CNN that they saw three men in the van, with two fleeing on foot after the other was apprehended.

The Associated Press reports that Finsbury Park Mosque, one of four mosques in the Islington borough, had been associated with extremist ideology in the wake of the 9/11 attacks in the US. The mosque was closed and later reorganized and has not been associated with radical views for more than a decade.

The incident comes at a time when Londoners are on edge. On June 3, a van drove into a crowd of people walking on the London Bridge, followed by knife attacks, leaving eight dead and many wounded. Police killed three Muslim extremists who carried out the attack. That incident came just a week after the Manchester Arena attack, which killed 22 and left more than 100 injured.